CVE-2018-6789

CRITICALNVD 9.89.8—

9.8

An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.

CVSS v3: 9.8
EG Score: 9.8(high)
EPSS: 99.5%
KEV: ⚠ Exploited

Published

February 8, 2018

Last Modified

November 7, 2025

References (27)

cve@mitrehttp://openwall.com/lists/oss-security/2018/02/10/2
cve@mitrehttp://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html
cve@mitrehttp://www.openwall.com/lists/oss-security/2018/02/07/2
cve@mitrehttp://www.securityfocus.com/bid/103049
cve@mitrehttp://www.securitytracker.com/id/1040461
cve@mitrehttps://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/
cve@mitrehttps://exim.org/static/doc/security/CVE-2018-6789.txt
cve@mitrehttps://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1
cve@mitrehttps://lists.debian.org/debian-lts-announce/2018/02/msg00009.html
cve@mitrehttps://usn.ubuntu.com/3565-1/
cve@mitrehttps://www.debian.org/security/2018/dsa-4110
cve@mitrehttps://www.exploit-db.com/exploits/44571/
cve@mitrehttps://www.exploit-db.com/exploits/45671/
af854a3a-2127-422b-91ae-364da2661108http://openwall.com/lists/oss-security/2018/02/10/2
af854a3a-2127-422b-91ae-364da2661108http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html

Patch Availability(1)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
ubuntu	eximon4 (4.86.2-2ubuntu2.3) @ xenial	2026-05-26	ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

UbuntuUSN-3565-1MEDIUM
Exim vulnerability

Data Freshness Timeline

(refreshed 8× in last 7d / 8× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-27 20:35 UTCkev_newly_listed
2026-05-27 13:38 UTCepss_batch
2026-05-26 19:26 UTCEG score recompute
2026-05-26 19:26 UTCVendor advisory
2026-05-26 19:26 UTCGHSA enrichment
2026-05-26 19:13 UTCkev_newly_listed
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(6)

What is CVE-2018-6789?

CVE-2018-6789 is a critical vulnerability published on February 8, 2018. An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.

When was CVE-2018-6789 disclosed?

CVE-2018-6789 was first published in the National Vulnerability Database on February 8, 2018, with the most recent update on November 7, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2018-6789 actively exploited?

Yes. CISA added CVE-2018-6789 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Exim Exim. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.

What is the CVSS score of CVE-2018-6789?

CVE-2018-6789 has a CVSS v3 base score of 9.8 (NVD).

Which products are affected by CVE-2018-6789?

CVE-2018-6789 affects Exim Exim. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.

How do I remediate CVE-2018-6789?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-6789, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2018-6789

Published

Last Modified

References (27)

Patch Availability(1)

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(6)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2018-6789?

Same vendor

Same CWE

CVE-2018-6789

📅 Published

🔄 Last Modified

🔗 References (27)

Patch Availability(1)

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(6)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2018-6789?

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References (27)

Frequently asked(6)

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